快猫短视频

Boston

WE NOW have a new weapon in the hunt for one of biology鈥檚 biggest
prizes鈥攕tem cells that can regenerate human tissues. It鈥檚 a genetic
fingerprint that will allow biologists to pick out stem cells from millions of
other cells.

Stem cells could eventually be used to grow perfectly matched replacement
tissues or organs for transplants. Stem cells that have the capacity to turn
into any kind of tissue can be found in human embryos and, researchers recently
claimed, in adult bone marrow too
(快猫短视频, 26 January 2002, p 4).
But forcing these cells to develop into a particular tissue or organ is
still tricky.

So other scientists are trying to track down more limited stem cells that are
already primed to become certain tissues. They have already found blood-forming
stem cells, for example. And researchers believe that stem cells may exist in
other organs like the heart, lung and pancreas. But so far they鈥檝e failed to
track down these elusive cells, perhaps because there are so few of them.

To help in the hunt for these specific stem cells, Douglas Melton, a cellular
biologist from Harvard University went looking for their unique pattern of gene
expression. His lab used DNA microarrays to compare embryonic stem cells, neural
stem cells and blood-forming stem cells from mice, and found that of thousands
of genes expressed, only 230 were common to all three kinds.

鈥淭his will be a potential fingerprint,鈥� says stem cell biologist Diane Krause
of Yale University. She says that similar studies have already looked at the
criteria that define blood-forming stem cells. But Melton鈥檚 work is novel
because it searches for common factors among unrelated kinds of stem cells. 鈥淚
think it鈥檚 a very good idea,鈥� says Krause.